altĕr-ŭter, altĕrū̆tra (more freq. than altera utra), altĕrū̆trum (more freq. than alterum utrum), adj. (in the obliq. cas. arch. alterutrius, alterutri, etc.; cf. Prisc. p. 667; 693 P.; gen. and dat. f. alterutrae, Charis. p. 132 ib.).
I One of two , the one or the other , either , no matter which (rare but class.): AD. ALTERVTRVM. SIBI. REDD( iderunt ), Carm. Fr. Arv. 28: video esse necesse alterutrum, Cic. Div. in Caecil. 18: si in alterutro peccandum sit, malo viderinimis timidusquam parum prudens, id. Marcell. 7; so id. Fam. 6, 3; 9, 6; id. Att. 10, 1; Cael. ap. Cic. Fam. 8, 8 fin. : Alterutrum velox victoria fronde coronet, * Hor. Ep. 1, 18, 64; Nep. Dion, 4, 1.—With both parts declined (prob. only in the two foll. exs.): alteriusutrius causā, Cato ap. Prisc. p. 693 P.: longitudo alteriusutrius, Cic. Prot. Fragm. ib.—
II = uterque, both : necessarium fuit alterutrum foris et sub dio esse, Col. praef. 12.